P15 The value of feature-tracking cardiac magnetic resonance imaging in detecting myocardial dysfunction in patients with idiopathic ventricular arrhythmias

ObjectiveTo investigate the added value of cardiac magnetic resonance (CMR) imaging in patients with idiopathic ventricular arrhythmias (VAs) and structurally normal hearts.MethodsSingle centre prospective study in 72 patients (mean age 46 ± 16 years; 53% females) with frequent premature ventricular contractions (PVCs ≥ 500/24h) and/or non-sustained ventricular tachycardia (NSVT), an otherwise normal electrocardiogram, normal echocardiography, and no coronary artery disease.ResultsCMR provided an additional diagnostic yield in 54.2% of patients. The most prevalent diagnosis was previous myocarditis (23.6%), followed by possible PVC-related cardiomyopathy (20.8%), non-ischaemic cardiomyopathy (8.3%) and ischaemic heart disease (1.4%). Predictors of abnormal findings on CMR were male gender, age, and PVCs/NSVT non-outflow tract-related or with multiple morphologies. Patients with VAs had impaired peak left ventricular (LV) global radial strain (GRS) compared with controls (28.88% (IQR: 25.87% to 33.97%) vs. 36.65% (IQR: 33.19% to 40.2%), p < 0.001) and a global circumferential strain (GCS) (-17.66% (IQR: -19.62% to -16.23%) vs. -20.66% (IQR: -21.72% to -19.6%), p < 0.001). Peak LV GRS showed a good diagnostic accuracy in detecting patients from the control subjects (AUC: 0.78 (95% CI: 0.69–0.86), p < 0.001). Moreover, Peak LV GRS and GCS could differentiate between the different categories of patients.ConclusionCMR can detect abnormalities and incipient contractile dysfunction in a significant proportion of patients with frequent idiopathic VAs, not identified on routine diagnostic work-up. Male gender, age and non-outflow tract PVC origin can be used as clinical indicators for CMR referral.